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Molecular Characterization of Enterotoxin-Producing Escherichia coli Collected in 2011-2012, Russia.

Kartsev NN, Fursova NK, Pachkunov DM, Bannov VA, Eruslanov BV, Svetoch EA, Dyatlov IA - PLoS ONE (2015)

Bottom Line: One isolate ETEC_Ef-6 was found to be a multidrug-resistant (MDR) pathogen that carried both the beta-lactamase gene and class 1 integron.These data suggest the circulation of ETEC in Russia.Further investigations are necessary to study the spread of the revealed ETEC sequence types (STs) and serotypes.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Microbiology, State Research Center for Applied Microbiology and Biotechnology, Obolensk, Russian Federation.

ABSTRACT
Enterotoxin-producing Escherichia coli (ETEC) are one of the main causative agents of diarrhea in children especially in developing countries and travel diarrhoea in adults. Pathogenic properties of ETEC associated with their ability to produce a heat-stable (ST) and/or heat-labile (LT) enterotoxins, as well as adhesins providing bacterial adhesion to intestinal epithelial cells. This study presents the molecular characterization of the ETEC isolates collected from the Central and Far-Eastern regions of Russia in 2011-2012. It was shown that all ETEC under study (n=18) had the heat-labile enterotoxin-coding operon elt, and had no the genes of the heat-stable enterotoxin operon est. DNA sequencing revealed two types of nucleotide exchanges in the eltB gene coding subunit B of LT in isolates collected from Cherepovets city (Central region, Russia) and Vladivostok city (Far-East region, Russia). Only one ETEC strain carried genes cfaA, cfaB, cfaC and cfaD coding adhesion factor CFA/I. Expression of LT in four ETEC isolates in the agglutination reaction was detected using a latex test-system. The isolates were assigned to serogroups O142 (n = 6), О6 (n = 4), О25 (n = 5), О26 (n = 2), and O115 (n = 1). Genotyping showed that they belonged to an earlier described sequence-type ST4 (n = 3) as well as to 11 novel sequence-types ST1043, ST1312, ST3697, ST3707, ST3708, ST3709, ST3710, ST3755, ST3756, ST3757 and ST4509. The ETEC isolates displayed different levels of antimicrobial resistance. Eight isolates were resistant to only one drug, three isolates-to two drugs, one isolate-to three drugs, two isolates-to four antibacterials, and only one isolate to each of the five, six and ten antibacterials simultaneously. Genetic determinants of the resistance to beta-lactams and other classes of antibacterials on the ETEC genomes were identified. There are blaTEM (n = 10), blaCTX-M-15 (n = 1), class 1 integron (n = 3) carrying resistance cassettes to aminoglycosides and sulphonamides dfrA17-aadA5 and dfrA12-orfF-aadA2. One isolate ETEC_Ef-6 was found to be a multidrug-resistant (MDR) pathogen that carried both the beta-lactamase gene and class 1 integron. These data suggest the circulation of ETEC in Russia. Further investigations are necessary to study the spread of the revealed ETEC sequence types (STs) and serotypes. Their role in the etiology of diarrhea should be also estimated.

No MeSH data available.


Related in: MedlinePlus

MLST phylogenetic tree of the 14 ETEC strains as reconstructed from the sequences of seven “housekeeping” genes.Phylogenetic tree constructed after assembly and alignment of MLST DNA sequences using the Mega 6 program. MLST and RAPD experiments are described in Materials and Method.
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pone.0123357.g002: MLST phylogenetic tree of the 14 ETEC strains as reconstructed from the sequences of seven “housekeeping” genes.Phylogenetic tree constructed after assembly and alignment of MLST DNA sequences using the Mega 6 program. MLST and RAPD experiments are described in Materials and Method.

Mentions: The MLST analysis of ETEC isolates under study revealed 12 different sequence-types. It was shown that two strains from Cherepovets (ETEC_22-2V and ETEC_112-2V) and one strain from Vladivostok (ETEC_Ef 7) belonged to the previously known sequence-type ST4 that had been presented in the MLST database by the ETEC strain (ETEC 117/86) isolated in Germany in 1986. It should be noted that the latter belongs to О6 serogroup as do our strains ETEC_22-2V and ETEC_112-2V isolated from two patients and sour cream sample during the outbreak in Cherepovets in 2011. It is noteworthy that the Clonal complex ST10 which ST4 sequence-type belongs to is quite typical for ETEC isolates worldwide [7]. The fact that ETEC strains of the sequence-type ST4 were isolated not only from human (ETEC_22-2V) but also from sour cream (ETEC_112-2V) allows one to consider sour cream as a potential source of the outbreak in Cherepovets. This observation agrees with earlier reports stating milk and dairy products as a potential reservoir for ETEC-associated infections. In addition to the sequence-type ST4, 11 novel sequence-types (ST1043, ST1312, ST3697, ST3707, ST3708, ST3709, ST3710, ST3755, ST3756, ST3757, and ST4509) were described in our research. They differ from each other and from the ST4 by sets of "housekeeping gene" alleles. The most remote from the ST4 is ST4509 of the strain ETEC_85-17V. It differs by all seven gene alleles. Other STs differ from the ST4 by two to six gene alleles. The adk, fumC, icd and purA genes were the most variable, while the gyrB, recA and mdh genes were more conservative (Table 2). It is interesting that some isolates that differed in their sequence-types, serogroups and resistance genes were collected from one and the same patient, for example, ETEC_85-4V and ETEC_85-17V strains, and ETEC_73-7V and ETEC_73-10V strains were isolated from the patient 85 and patient 73 respectively. The analysis of the phylogenic tree structure and RAPD data of the ETEC strains described in our study allow one to combine the ST4, ST1312, ST3709, ST3755, and ST3697 that are genetically related into one cluster, the ST3708 and ST1043 into other cluster, while remaining STs were unclustered (Fig 2).


Molecular Characterization of Enterotoxin-Producing Escherichia coli Collected in 2011-2012, Russia.

Kartsev NN, Fursova NK, Pachkunov DM, Bannov VA, Eruslanov BV, Svetoch EA, Dyatlov IA - PLoS ONE (2015)

MLST phylogenetic tree of the 14 ETEC strains as reconstructed from the sequences of seven “housekeeping” genes.Phylogenetic tree constructed after assembly and alignment of MLST DNA sequences using the Mega 6 program. MLST and RAPD experiments are described in Materials and Method.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414545&req=5

pone.0123357.g002: MLST phylogenetic tree of the 14 ETEC strains as reconstructed from the sequences of seven “housekeeping” genes.Phylogenetic tree constructed after assembly and alignment of MLST DNA sequences using the Mega 6 program. MLST and RAPD experiments are described in Materials and Method.
Mentions: The MLST analysis of ETEC isolates under study revealed 12 different sequence-types. It was shown that two strains from Cherepovets (ETEC_22-2V and ETEC_112-2V) and one strain from Vladivostok (ETEC_Ef 7) belonged to the previously known sequence-type ST4 that had been presented in the MLST database by the ETEC strain (ETEC 117/86) isolated in Germany in 1986. It should be noted that the latter belongs to О6 serogroup as do our strains ETEC_22-2V and ETEC_112-2V isolated from two patients and sour cream sample during the outbreak in Cherepovets in 2011. It is noteworthy that the Clonal complex ST10 which ST4 sequence-type belongs to is quite typical for ETEC isolates worldwide [7]. The fact that ETEC strains of the sequence-type ST4 were isolated not only from human (ETEC_22-2V) but also from sour cream (ETEC_112-2V) allows one to consider sour cream as a potential source of the outbreak in Cherepovets. This observation agrees with earlier reports stating milk and dairy products as a potential reservoir for ETEC-associated infections. In addition to the sequence-type ST4, 11 novel sequence-types (ST1043, ST1312, ST3697, ST3707, ST3708, ST3709, ST3710, ST3755, ST3756, ST3757, and ST4509) were described in our research. They differ from each other and from the ST4 by sets of "housekeeping gene" alleles. The most remote from the ST4 is ST4509 of the strain ETEC_85-17V. It differs by all seven gene alleles. Other STs differ from the ST4 by two to six gene alleles. The adk, fumC, icd and purA genes were the most variable, while the gyrB, recA and mdh genes were more conservative (Table 2). It is interesting that some isolates that differed in their sequence-types, serogroups and resistance genes were collected from one and the same patient, for example, ETEC_85-4V and ETEC_85-17V strains, and ETEC_73-7V and ETEC_73-10V strains were isolated from the patient 85 and patient 73 respectively. The analysis of the phylogenic tree structure and RAPD data of the ETEC strains described in our study allow one to combine the ST4, ST1312, ST3709, ST3755, and ST3697 that are genetically related into one cluster, the ST3708 and ST1043 into other cluster, while remaining STs were unclustered (Fig 2).

Bottom Line: One isolate ETEC_Ef-6 was found to be a multidrug-resistant (MDR) pathogen that carried both the beta-lactamase gene and class 1 integron.These data suggest the circulation of ETEC in Russia.Further investigations are necessary to study the spread of the revealed ETEC sequence types (STs) and serotypes.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Microbiology, State Research Center for Applied Microbiology and Biotechnology, Obolensk, Russian Federation.

ABSTRACT
Enterotoxin-producing Escherichia coli (ETEC) are one of the main causative agents of diarrhea in children especially in developing countries and travel diarrhoea in adults. Pathogenic properties of ETEC associated with their ability to produce a heat-stable (ST) and/or heat-labile (LT) enterotoxins, as well as adhesins providing bacterial adhesion to intestinal epithelial cells. This study presents the molecular characterization of the ETEC isolates collected from the Central and Far-Eastern regions of Russia in 2011-2012. It was shown that all ETEC under study (n=18) had the heat-labile enterotoxin-coding operon elt, and had no the genes of the heat-stable enterotoxin operon est. DNA sequencing revealed two types of nucleotide exchanges in the eltB gene coding subunit B of LT in isolates collected from Cherepovets city (Central region, Russia) and Vladivostok city (Far-East region, Russia). Only one ETEC strain carried genes cfaA, cfaB, cfaC and cfaD coding adhesion factor CFA/I. Expression of LT in four ETEC isolates in the agglutination reaction was detected using a latex test-system. The isolates were assigned to serogroups O142 (n = 6), О6 (n = 4), О25 (n = 5), О26 (n = 2), and O115 (n = 1). Genotyping showed that they belonged to an earlier described sequence-type ST4 (n = 3) as well as to 11 novel sequence-types ST1043, ST1312, ST3697, ST3707, ST3708, ST3709, ST3710, ST3755, ST3756, ST3757 and ST4509. The ETEC isolates displayed different levels of antimicrobial resistance. Eight isolates were resistant to only one drug, three isolates-to two drugs, one isolate-to three drugs, two isolates-to four antibacterials, and only one isolate to each of the five, six and ten antibacterials simultaneously. Genetic determinants of the resistance to beta-lactams and other classes of antibacterials on the ETEC genomes were identified. There are blaTEM (n = 10), blaCTX-M-15 (n = 1), class 1 integron (n = 3) carrying resistance cassettes to aminoglycosides and sulphonamides dfrA17-aadA5 and dfrA12-orfF-aadA2. One isolate ETEC_Ef-6 was found to be a multidrug-resistant (MDR) pathogen that carried both the beta-lactamase gene and class 1 integron. These data suggest the circulation of ETEC in Russia. Further investigations are necessary to study the spread of the revealed ETEC sequence types (STs) and serotypes. Their role in the etiology of diarrhea should be also estimated.

No MeSH data available.


Related in: MedlinePlus